api: cg_set_control_value strncat fix

cg_set_control_value function contains strncat which uses
sizeof(string) for limitation size which is bogus. This patch fixes it.

Signed-off-by: Ivana Hutarova Varekova <varekova@redhat.com>
Signed-off-by: Jan Safranek <jsafrane@redhat.com>

diff --git a/src/api.c b/src/api.c
index 96495c325f7926dcd1a9580e729aad9af195c1b1..d5022c2b791da002ba026b58cf78234893926f73 100644 (file)
--- a/src/api.c
+++ b/src/api.c
@@ -1286,18 +1286,34 @@ static int cg_set_control_value(char *path, const char *val)
                         * does not exist. So we check if the tasks file
                         * exist. Before that, we need to extract the path.
                         */
-                       int len = strlen(path);
+                       char *path_dir_end;
+                       char *tasks_path;
 
-                       while (*(path+len) != '/')
-                               len--;
-                       *(path+len+1) = '\0';
-                       strncat(path, "tasks", sizeof(path) - strlen(path));
-                       control_file = fopen(path, "re");
+                       path_dir_end = strrchr(path, '/');
+                       if (path_dir_end == NULL)
+                               return ECGROUPVALUENOTEXIST;
+                       path_dir_end = '\0';
+
+                       /* task_path contain: $path/tasks */
+                       tasks_path = (char *)malloc(strlen(path) + 6 + 1);
+                       if (tasks_path == NULL) {
+                               last_errno = errno;
+                               return ECGOTHER;
+                       }
+                       strcpy(tasks_path, path);
+                       strcat(tasks_path, "/tasks");
+
+                       /* test tasks file for read flag */
+                       control_file = fopen(tasks_path, "re");
                        if (!control_file) {
-                               if (errno == ENOENT)
+                               if (errno == ENOENT) {
+                                       free(tasks_path);
                                        return ECGROUPSUBSYSNOTMOUNTED;
+                               }
                        }
+
                        fclose(control_file);
+                       free(tasks_path);
                        return ECGROUPNOTALLOWED;
                }
                return ECGROUPVALUENOTEXIST;